scope hei_bit_string.hpp for external use

This header will been needed by user applications.

Signed-off-by: Zane Shelley <zshelle@us.ibm.com>
Change-Id: I4eae57c63e3d314d87faed364a3c314c2300d20a
diff --git a/src/register/hei_register.hpp b/src/register/hei_register.hpp
index e0473aa..ff630f3 100644
--- a/src/register/hei_register.hpp
+++ b/src/register/hei_register.hpp
@@ -1,7 +1,7 @@
 #pragma once
 
+#include <hei_bit_string.hpp>
 #include <hei_includes.hpp>
-#include <util/hei_bit_string.hpp>
 
 namespace libhei
 {